Buoyant Propeller



MFETERS. PHDTuLIYMaGRAPHEn WASHINGTON D ITED STATES PATENT OFFICE.

WILLIAM LANSDELL, OF MEMPHIS, TENNESSEE.

BUOYANT PROPELLER.

Specification of Letters Patent No. 12,955, dated May 29, 1855.

To all whom 'it may concern:

Be it known that I, WILLIAM LANSDELL,

,of Memphis, Tennessee,have invented a new and improved mode of constructing and propelling structures for river and ocean navigation by a combination which I propose to name a marine locomotive; and I do hereby declare that the following is a full and eXact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

The nature of my invention consists in the construction of two segmentary cylinders, composed of hollow, water-tight threads arranged in the form of a screw, for the double purpose of supporting a superstructure by their power of flotation, and of giving motion to the same by their revolution in the water.

In the drawing four segments, threads, or oats are represented at A, B, C, D, but I do not confine myself to this or any other particular number. These segments or threads are separated by spiral water spaces, through the whole length of the threads, and surround an open space in the center which is framed and connected with the bearings, as a hollow shaft, admitting the free passage of the water. The ends of the segments are made sharp, somewhat in the form of wedges, having an increased pitch on one side, and having projecting flanges on the other side when the pitch is regular. These flanges are represented at a, a, a, a, and the increased pitch is seen on the other edge at b, b, b, b. The object of the flange is to assist in propelling, though I sometimes propose to use the hollow threads without the flange. exactly reversed at the opposite end of the screw or compound cylinder; the effect of which is to produce a drawing power at one end and a propelling power at the other. The peculiar form of these segmentary and buoyant threads with the open spaces between them and in the center, is designed to diminish the resistance of the immersed sec-V tion and to facilitate the escape of the water.

This arrangement is.

propose to connect the two cylinders or screws by any suitable frame work for the support of any desirable form of superstructure.

The cross-section or break in the screw represented at e, c, e, e, is designed merely to aord means of additional bracing and connection of the two cylinders and for the support of the superstructure. These may be omitted, or increased in number according to the length of the structure.

Power may be applied to the cylinders by means of a steam engine or other motive power, according to any known mode of application; but I propose to arrange the two cylinders in such a manner that they shall revolve in opposite directions, when using right and left-hand threads.

Vhat I do claim isl. The combination of the hollow threads in the form described, with the central and lateral water spaces, forming the threads of a screw, and securing both flotation and propulsion.

2. I also claim the use of the flange arranged on the regular edge of the segments having the true pitch of the regular screw.

3. I claim also the peculiar wedgelike form of the ends of the segments, having the eifect to diminish the resistance of the immersed section at the head, while it increases the propelling force at the stern; I do not conline myself to the exact proportions of the pitch or form of the ends of the screw or its threads as represented in the drawing.

VILLIAM LANSDELL.

Witnesses:

N. CALLAN, FRED. C. STARTER. 

